Experimental study of the effect of inlet flow characteristics and chamber length on partially premixed flame dynamics, in the mesoscale cylindrical reactor of constant diameter with different lengths (original) (raw)

2020, Modares Mechanical Engineering

In this paper, the experimental study of partially premixed combustion of pure methane/ oxygen has been implemented in a 5 mm diameter meso-scale quartz reactor that has 1 mm wall thickness and 5, 10, and 15 cm lengths. Mixing ratios of 25 % , 50 % and 75 % have been used for partially premixed combustion tests. Experimental results including the factors affecting flame regimes, formation range, flame dynamics, and the outer wall temperature distribution of the reactor have been analyzed. The tests were performed in an axisymmetrically centered cylinder combustion chamber (uniform co-axial flow) and laminar flow regimes. In most partially premixed combustion experiments, the Repetitive Extinction and Re-Ignition (RERI) flame, which had an optimal heat distribution throughout the reactor, have been observed. The flame dynamics were mostly affected by changes in mixing ratio, reactor length, oxygen flow rate, and finally fuel flow rate (equivalence ratio) respectively. Also, observations revealed that by increasing the reactor length due to the appropriate time for homogenization of the mixture, differences in the flame formation interval were reduced in different ratios of the reactant pre-mixes.